1. Field
This disclosure relates generally to electronic circuits, and more specifically, to a single-supply, single-ended level conversion circuit for multiple power supply integrated circuits.
2. Related Art
Lower power consumption has been gaining importance in integrated circuit data processing systems due to, for example, wide spread use of battery powered portable and handheld applications. Reducing leakage current is becoming an increasingly important factor in extending battery life.
In multi-core system-on-a-chip (SoC) integrated circuits, two or more power supply domains are used to achieve optimum speed, power, and reliability. Logic signals are conveyed from one power supply voltage domain to another power supply voltage domain using level conversion circuits implemented at a boundary between the domains. A leakage current path may develop if the power supply voltage from one domain is insufficient to fully turn off certain transistors of the level conversion circuit. A conventional level converter circuit may require two stages to fully level convert the logic signal. A first stage is supplied with the power supply voltage from one domain and a second stage is supplied with the power supply voltage from the other domain. However, using a level conversion circuit supplied by two power supply voltages causes routing congestion at the boundary between the two power supply domains. Also, there may be constraints on which power supply voltage is higher and constraints regarding power up and power down sequences. In addition, a conventional level conversion circuit may require differential input signals. Further, a conventional level conversion circuit may require the use of lower threshold voltage (VT) transistors or dynamic precharge circuitry synchronized with data and clock signals, adding complexity to the level conversion circuit.
Therefore, what is needed is a level conversion circuit for use in an integrated circuit having multiple power supply voltage domains that solves the above problems.